Mechanically held latch attachment for an electromagnetic relay

ABSTRACT

A latching attachment is provided for an electromagnetic relay. An insert for the relay movable contact carrier is employed in association with the latching attachment and the insert has at least one projection extending therefrom. The latching attachment includes a rotatable plate, mounted adjacent the insert projection and having an aperture therethrough and the plate is biased into a position in which the aperture is less than fully aligned with the projection on the insert, thereby preventing return of the contact carrier from its energized position to its de-energized position after the relay has been energized and subsequently de-energized. Manual and electromagnetic operators are provided for rotating the plate aperture into full alignment with the insert projection for releasing the relay contact carrier.

United States Patent 11 1 1111 3,812,440 Cook 5] May 21, 1974 MECHANICALLY HELD LATCH 3,238,329 3/1966 Russo 335/131 ATTACHMENT FOR AN 2,887,883 5/1959 Zipper 74/2 ELECTROMAGNETIC RELAY P I E H 1d B rzmary xammer-- aro roome [75 Inventor Dav'd Langman Cook swmdon Attorney, Agent, or FirmHar0ld J. Rathbun England [73] Assignee: Square D Company, Park Ridge, Ill. [57] ABSTRACT [22] Filed: Nov. 17, 1972 A latching attachment is provided for an electromagnetic relay. An insert for the relay movable contact [21] Appl' 307746 carrier is employed in association with the latching attachment and the insert has at least one projection ex- [30] Foreign Application Priority Data tending therefrom. The latching attachment includes a Nov. 19, 1971 Great Britain 53731 /71 rotatable Plate, mounted adjacent the insert Projection and having an aperture therethrough and the plate is 52 1 335 1 7 200 p 5 32 biased into a position in which the aperture is less than 5 1 1111. C1. H0lh 9/22 fully aligned with me projection on we insert thereby 53 Field f Search u 3 35 32 1 4 1 5 preventing return of the contact carrier from its ener- 335/1 167 g 170 253 255 12 113; gized position to its de-energized position after the 2 0 7 2 relay has been energized and subsequently deenergize'd. Manual and electromagnetic operators are 5 References Cited provided for rotating the plate aperture into full align- UNITED STATES PATENTS ment with the insert projection for releasing the relay contact carrier. 646.721 4/1900 Baker et a] 200/l69 PB 1.467.664 9/1923 Yonge 200/169 PB 8 Claims, 6 Drawing Figures FAIENTEDMAYZI m4 3812, 240

sum 2 OF 3 92 F l G. 2

FAIENTEDMAY'A 1974 I 3,812,440 SHEET 3 0E3 FIGS MECHANICALLY HELD LATCH ATTACHMENT FOR AN ELECTROMAGNETIC RELAY This invention relates to latching mechanisms and, more particularly, to a mechanically held latch attachment suitable for association with a manual or electromagnetic operator and control contacts to provide latching of the control contacts in predetermined positions following the initial energization and subsequent de-energization of an electromagnetic relay and selective release of the control contacts from the predetermined positions by actuation of an electromagnetic or manual operator.

It is an object of the present invention to provide an improved latch attachment which is relatively inexpensive to manufacture, which may be easily and quickly installed on an electromagnetic relay and which may be simply released, selectively, by a manual or by an electromagnetic operator.

Another object of the present invention is to provide such a latch attachment which may be partially disassembled for the purpose of removing or replacing some of its component parts without removing the entire latch attachment from the relay upon which it is mounted.

Other objects, features and advantages of the invention will become apparent from the following descrip tion of a preferred embodiment, taken together with the attached drawings thereof, in which:

FIG. 1 is a partially exploded perspective view showing a latch attachment, constructed in accordance with the invention, in its housing, a contact carrier insert employed with the latch attachment, a relay contact carrier, two relay contact blocks, and one of two retaining springs for the relay;

FIG. 2 is a view in cross section, taken along line 2-2 in FIG. 1, of the latchattachment;

FIG. 3 is an end view, in side elevation and partially broken away, showing the latch attachment in its blocking position and portions of a relay to which it is attached;

7 FIG. 4 is a view, partially in cross section and partially broken away, showing the latch attachment, positioned for permitting movement of a relay contact carrier, in place on the contact blocks of a relay, together with the relay movable contact carrier and the contact carrier insert;

FIG. 5 is a view, partially in cross section, partially exploded and with the converter spring removed, showing portions of the movable armature, the magnet core, the converter and the latch plate assembly employed in the latch attachment; and

FIG. 6 is a view, partially in cross section, showing portions of the helical camming surface in the inner wall of the magnet core.

Referring now to FIG. 1, there is shown a mechanically held latch attachment, generally designated 10, and its associated carrier insert 12. Latch attachment 10 includes a molded plastic lower (or rear) housing 14 and mounted above (or forwardly of) rear housing 14 an annular metallic electromagnetic coil 16 and a U- shaped magnet frame 18 surrounding portions of the top (or front) and two sides of coil 16. An annular magnet core support plate 19 (see FIG. 2), having recesses 20 in the left and right edges thereof and pairs of ribs 21 (FIG. 4) on the sides edges thereof, is provided and is secured to magnet frame 18 by a pair of screws 22 which pass through recesses 20 and are secured within threaded holes 23 in magnet frame 18. A pair of metallic retaining springs 24 extend around upper and lower portions of rear housing 14 and are releasably secured at the rear thereof to upper and lower pairs of bosses 25a and 25b, respectively, on the rear surface 26 of housing 14 and at the front thereof extend through recesses 27 (see FIG. 3) in coil 16 and are bent around the pairs of ribs 21 (see FIG. 4).

Magnet frame 18 and coil 16 have aligned openings 28 and 29 (see FIG. 2), respectively, therethrough and an annular operator or armature 30 (to be discussed in greater detail below), having a central opening 32, extends through openings 28 and 29 forwardly of frame 18. A compression spring 34 is seated-between the front surface 35 of frame 18 and shoulder 36 defined by a peripheral groove 38 (see FIG. 2) in armature 30 and is arranged to urge armature 30 into a forward position in opening 29 of coil 18. Coil terminal portions 40 (see FIG. 3) extend outwardly from opposite sides of coil 18 intermediate the front and rear surfaces thereof, and suitable wiring clamps 42 are secured to the respective coil terminals 40 by screws 44. A pair of mounting lugs 46 and 48, integral with and extending rearwardly of lower molded plastic housing 14, are pro vided and each of mounting lugs 46 and 48 has a stepped clamping surface 50 (only one clamping surface 50 shown in FIG. 1).

Also shown in FIG. 1 are a left hand contact block 52, a right hand contact block 54, and a relay movable contact carrier 56 having at its frontor upper end portion a pair of rearwardly extending spaced recesses 58 each having at its rear end a recess 60 extending laterally outwardly therefrom. Each of the contact blocks 52 and 54 has a pair of stepped opposite end surfaces 62 and 64, respectively (only one stepped end surface shown for each in FIG. 1), providing pairs of recesses 66 and 68, respectively, and pairs of clamping surfaces 70 and 72, respectively. As is well known to those skilled in the art to which the invention pertains, when the relay is assembled, the contact blocks 52 and 54 are mounted on a relay base (not shown) on opposite sides of relay contact carrier 56 and the stepped end surfaces 62 and 64 on the contact blocks 52 and 54, respectively, cooperate to define at each end of the contact blocks a single recess 66, 68 and a single clamping surface 70, 72 about which retaining clips 74 (only one shown in FIG. 1), rotatably secured to the lower portion of the relay base, may be passed to hold the contact blocks 52 and 54 firmly in place on the relay base in cooperative relation with the relay contact carrier 56. Carrier insert 12 has a main body portion 76 including a groove 78 (only one groove 78 clearly shown in FIG. 1) in each of the opposite end portions thereof, a pair of spaced projections 80 and 82. (each having an upper step portion 80a and 82a, respectively, defining a latching surface 80band 82b, respectively) extending forwardly of body portion 76 and a pair of spaced mounting feet 84, each arranged tobe secured in one of the pair of recesses 58 60 of relay movable contact carrier 52, extending rearwardly from main body portion 76.

The timer attachment 10 may be simply and quickly installed in place on a relay without removing the relay from a panel on which it is mounted by releasing retaining clips 74 removing contact blocks 52 and 54 and removing a non-functional insert (not shown) which is inserted into the recesses 58, 60 in relay contact carrier 56 during initial assembly of the relay. The mounting feet 84 of timer attachment carrier insert 12 may then be inserted in place in the pairs of recesses 58, 60 in carrier 56, contact blocks'52 and 54 assembled in place around carrier 56 and the latch attachment l installed by positioning the mounting lugs 46 and 48 of the lower housing 14 in the recesses 66, 68 at each end of contact blocks 52 and 54 and then rotating the retaining clips 74 (FIGS. 1 and 4) into place against clamping surfaces 50 and 70, 72. As is best shown in FIG. 4, carrier insert 12, which is preferably molded from a resilient plastic material, is provided with a pair of pads 85 extending downwardly from body portion 76 and has a central groove 86 between mounting feet 84. When carrier insert, 12 is mounted in recesses 58, 60 of contact carrier 56,'pads 85 provide a snug fit between body portion 76 of insert 12 and contact carrier 56 after mounting feet 84 have been engaged in recesses 58, 60 of contact carrier 56. Groove 86 facilitates flexing of body portion 76 during mounting of carrier insert 12 on contact carrier 56 and grooves 78 may be aligned with cooperating ribs 89 in housing 14.

Referring now to FIGS. 2 and 3, wherein the latch attachment is shown in greater detail, electromagnetic coil 16 is shown mounted within coil frame 18 by metallic plate 19 which has a central opening 87 extending therethrough and which is secured to frame 18 by screws 22. Armature 30 extends downwardly into opening 29 in coil 16 and has an annular rib 88 formed at the lower end thereof and an annular groove 90 formed in the lower surface thereof. A' stepped annular armature guide 92 is provided above side 88 between coil 16 and armature 30 and has an upper neck portion extending from a shoulder 94 upwardly into the space 96 between frame 18 and armature 30. A wave washer 98 is seated between frame 18 and the generally planar surface formed by the cooperation of the upper surface of coil 16 and shoulder 94. An annular shading coil 100 is seated in groove 90 in armature 30.

A converter assembly, generally designated 102, is

disposed below armature 30 and passageway 29 and is arranged to convert longitudinal movement, of armature 30 into limited rotational movement of a latching plate 104. Converter assembly 102 includes an annular metallic magnet core 106 force fitted in opening 87 in plate 19 and having a central opening 108. An annular molded plastic converter shaft' 110, having an upper surface 111 (FIG. 5), is disposed within central opening 108 of core 106 and is arrangedto .be engaged by a bottom surface 112 of armature 30 when armature 30 is moved downwardly againstthe force of compression spring 34.'Converter'-shaft 1-10 is provided with a central opening 113 (having a diameter which is less than the diameter of central opening 32 of armature 30), a pair of helical projections 114 extending outwardly from the surface of shaft 110 and three splines 116 (FIG. 2) extending upwardly a predetennined distance from the bottom of shaft 110. A metallic washer 118 defining an upper spring'seat has three splines (not shown) arranged to mesh with splines 116 of converter shaft 110. An annular molded plastic converter guide 120 has splines (not shown), extending into a central opening 122 thereof and arranged to mesh with splines 116 of converter shaft 110, and an annular rib 124 excompression spring 127 is seated between upper surface 126 of converter guide 120 and seating surface dcfined by metallic washer 118.

Core 106 is provided with an inwardly projecting annular rib 128 at the top thereof and a molded plastic core insert 130 is snugly fit within central opening 108 tending around the outer'periphery thereof and, within rib 124, an upper surface 126 defining a spring seat. A

adjacent annular rib 128. Core insert 130 has a pair of helical slots 132 defining helicalcamming surfaces 133 (one surface 133 is shown in FIG. 6) formed in the inner surface 134 thereof and the camming surfaces 133 are arranged to cooperate with the helical projections 114 on converter shaft to rotate converter shaft 110 clockwise by a predetermined amount as it is urged downwardly by bottom surface 112 of armature 30.

Referring now to FIG. 5, portions of the converter assembly 102 are shown in greater detail. Latching plate 104 has a generally oblong shape and is provided with a pair of generally trapezoidal windows 136 and 138, a pair of bolt receiving apertures both designated 140, and a central opening 141. Converter guide has a pair of laterally extending rib portions 142 (only one portion 142 shown in FIG. 5) extending outwardly from opposite sides thereof and each having a bolt receiving aperature 144 arranged to be aligned with the bolt receiving apertures 140 in latching plate 104. Each of rib portions 142 is arranged to receive a threaded metallic nut plate 146 into which a bolt 148 may be threaded in'order to secure latch plate 104 to converter guide 120. j

In operation, when coil 16 is de-energized armature 30 is in its normal forwardly biased positionand the lower surface 112 thereof is spaced from converter shaft 110. Latching plate 104 has been rotated counterclockwise to its nonnal position by the force of spring 127, and windows 136 and 138 are less than fully aligned with latching surfaces 80b and 82b, respectively. When the relay is energized,contact carrier 56 is moved downwardly carrying insert '12 downwardly. When the relay subsequently becomes de energized, contact carrier 56 begins to be moved upwardly toward its normal position by a spring (not shown). Latching surfaces 80b and 80b of projections 80 and 82, respectively, come into contact with portions of latching plate 104 adjacent windows 136 and If the relay is subsequently energized, contact carrier 56 will again be moved downwardly but, as long as latching plate 104is in its normal position, the contact carrier 56 will be prevented from returning fully to its de-energized position. FIG. 3 shows latching plate 104 positioned for preventing movement of contact carrier 56 to its de-energized position.

When electromagnetic coil 16 is energized, armature 30 is moved downwardly against the force of spring 34 by the magnetic field generated inopening 29. Bottom surface 112 of annature 30 engages upper surface 111 of converter shaft 110 and moves shaft 110 downwardly. As shaft 110 is moved downwardly, helical projections 114 cooperate with the helical cammi'ng surfaces 133 provided in core insert and converter shaft 110, together with converter guide 130 and latching plate 104, are rotated clockwise. When latching plate .104 has been moved to its rotated position, windows 136 and 138 are fully aligned with projections 80 and 82, respectively, on carrier insert 12 and carrier insert 12 and movable contact carrier 56 are free to move between the energized and de-energized positions for the relay without restriction by the latch attachment.

The electrical latching operation is provided when coil 16 is de-energized. Converter shaft 110 is urged upwardly by spring 127 and armature 30 is urged to its normal forwardly biased position by compression spring 34. As converter shaft 110 moves upwardly, the helical projections 114 on shaft 110 and the helical camming surfaces 133 in the core insert 130 cooperate to rotate shaft 110 to its initial position in which windows l36'and 138 are in obstructing relationship with projections 80 and 82, respectively.

The latching attachment may be operated manually by inserting a thin rod through central openings 32, 29, 112 and 131 of armature 30, coil 16, converter shaft 110 and latching plate 104 and pushing the insert 12 and relay contact carrier 56 downwardly until projections 80 and 82 are disposed fully below latch plate 104. If coil 16 is de-energized, plate 104 rotates to its normal obstructing position. When the relay has been latched by latching attachment 10, it may be unlatched manually simply by pushing armature 30 downwardly against the forceof spring 34. When armature 30 is pushed downwardly, the converter shaft 110 is moved downwardly and rotated, as described above, and windows 136 and 138 of latching plate 104 is rotated into non-obstructing relationship with projections 80 and 82, respectively, on carrier insert 12.

The tight fit of the insert 12 on contact carrier 56 prevents loosening of the insert during service and, because of the overtravel of the contact carrier (relative to movement of a bridging contact) provided in vertical axis relays, a latching attachment constructed in accordance with the invention is readily adaptable for use without adjustment to individual relays of a particular type.

While the invention has been described with reference to a particular embodiment thereof, it will be understood by those skilled in the art that various modifications in form and detail may be made therein without department from the spirit and scope of the appended claims.

1 claim:

1. A latching attachment for a relay having a member movable between a first position corresponding to a first condition of the relay and a second position corresponding to a second conditionof the relay, the attachment comprising structure defining: a blocking mechanism arranged for rotationabout a fixed axis between a first rotary position in which the blocking mechanism is arranged to permit the movable member to be moved between its respective first and second positions'and a second rotary position in which the blocking mechanism is arranged to block movement of the movable member from its second position to its first position, and means for rotating the blocking mechanism comprising a second member-having a longitudinal dimension and being movable along the longitudinal dimension, and means for converting longitudinal movement of the second member to rotation of the blocking mechanism.

2. A latching attachment according to claim 1 further comprising an electromagnetic coil which surrounds at least a portion of the second member and is arranged to generate a magnetic field when energized, the second member being arranged to respond to a magnetic field and thereby defining an armature within the coil, the armature being normally biased into a first position when the electromagnetic coil is de-energized and being arranged to be moved longitudinally from the first position to a second position when the electromagnetic coil has been energized.

3. A latching attachment according to claim 2 wherein the armature has a shoulder on the outer periphery thereof and is normally biased into its first position by a compression spring seated between the electromagnetic coil and the shoulder.

4. A latching. attachment according to claim 1 wherein the means for converting comprises an annular outer member having a helical camming surface disposed inwardly thereof and an annular inner member movable longitudinally within the outer member, having one end thereof connected to the blocking mechanism and having a helical projection extending outwardly therefrom, the helical camming surface and the helical projection being arranged to engage each other in sliding relationship and thereby to cooperate to rotate the inner member by a predetermined amount when the inner member is moved longitudinally with respect to the outer member.

5. A latching attachment according to claim 4 wherein the annular inner member of the means for converting is movable longitudinally between first and second positions and the means for converting further comprises biasing means normally urging the inner member into its first position.

6. A latching attachment according to claim 5 wherein the outer member is secured to the electromagnetic coil and an annular space is provided be-' tween the outer and inner members and the biasing means comprises a compression spring seated in the an nular space and arranged to engage portions of the outer and inner members and to urge the inner member toward its first position.

7. A latching attachment according to claim 1 further comprising structure defining:

latching means arranged to be secured to the movable member of the relay adjacent the blocking mechanism, the latching means thereby being'arranged for movement between first and second positions, the blocking mechanism in its first rotary position being arranged to permit the latching means to be moved between its first and second positions and in its second rotary position being arranged to prevent return of the latching means from its second position to its first position.

8. A latching attachment according to claim 7 wherein the latching means comprises a protruding member extending from the movable member of the relay and the blocking mechanism includes a plate having an aperture therethrough, the; aperture being arranged to be fully aligned with the protruding member when the plate is in its first rotary position and thereby to permit the protruding member to pass therethrough when the protruding member is moved between its first and second positions and to be less than fully aligned with the protruding member when the plate is in its second rotary position and thereby to block movement of the protruding member and the movable member of the relay from their respective second positions to their respective first positions. 

1. A latching attachment for a relay having a member movable between a first position corresponding to a first condition of the relay and a second position corresponding to a second condition of the relay, the attachment comprising structure defining: a blocking mechanism arranged for rotation about a fixed axis between a first rotary position in which the blocking mechanism is arranged to permit the movable member to be moved between its respective first and second positions and a second rotary position in which the blocking mechanism is arranged to block movement of the movable member from its second position to its first position, and means for rotating the blocking mechanism comprising a second member having a longitudinal dimension and being movable along the longitudinal dimension, and means for converting longitudinal movement of the second member to rotation of the blocking mechanism.
 2. A latching attachment according to claim 1 further comprising an electromagnetic coil which surrounds at least a portion of the second member and is arranged to generate a magnetic field when energized, the second member being arranged to respond to a magnetic field and thereby defining an armature within the coil, the armature being normally biased into a first position when the electromagnetic coil is de-energized and being arranged to be moved longitudinally from the first position to a second position when the electromagnetic coil has been energized.
 3. A latching attachment according to claim 2 wherein the armature has a shoulder on the outer periphery thereof and is normally biased into its first position by a compression spring seated between the electromagnetic coil and the shoulder.
 4. A latching attachment according to claim 1 wherein the means for converting comprises an annular outer member having a helical camming surface disposed inwardly thereof and an annular inner member movable longitudinally within the outer member, having one end thereof connected to the blocking mechanism and having a helical projection extending outwardly therefrom, the helical camming surface and the helical projection being arranged to engage each other in sliding relationship and thereby to cooperate to rotate the inner member by a predetermined amount when the inner member is moved longitudinally with respect to the outer member.
 5. A latching attachment according to claim 4 wherein the annular inner member of the means for converting is movable longitudinally between first and second positions and the means for converting further comprises biasing means normally urging the inner member into its first position.
 6. A latching attachment according to claim 5 wherein the outer member is secured to the electromagnetic coil and an annular space is provided between the outer and inner members and the biasing means comprises a compression spring seated in the annular space and arranged to engage portions of the outer and inner members and to urge the inner member toward its first position.
 7. A latching attachment according to claim 1 further comprising structure defining: latching means arranged to be secured to the movable member of the relay adjacent the blocking mechanism, the latching means thereby being arranged for movement between first and second positions, the blocking mechanism in its first rotary position being arranged to permit the latching means to be moved between its first and second positions and in its second rotary position being arranged to prevent return of the latching means from its second position to its first position.
 8. A latching attachment according to claim 7 wherein the latching means comprises a protruding member extending from the movable member of the relay and the blocking mechanism includes a plate having an aperture therethrough, the aperture being arranged to be fully aligned with the protruding member when the plate is in its first rotary position and thereby to permit the protruding member to pass therethrough when the protruding member is moved between its first and second positions and to be less than fully aligned with the protruding member when the plate is in its second rotary position and thereby to block movement of the protruding member and the movable member of the relay from their respective second positions to their respective first positions. 